JP2010276173A - Vacuum insulation container and method of inserting sealed gas into the vacuum insulation layer - Google Patents

Abstract

The present invention provides a vacuum heat insulating container in which a sealed gas that sublimates into a solid at a temperature of liquid nitrogen such as carbon dioxide or liquid oxygen is sealed in a vacuum heat insulating layer, and a method for inserting the sealed gas into the vacuum heat insulating layer.
A vacuum heat insulating container (1) having a vacuum heat insulating layer (4), wherein a sealing gas (5) is sealed in the vacuum heat insulating layer (4). The sealed gas 5 is a gas at normal temperature, and when the cryogenic refrigerant 7 is put into the vacuum heat insulating container 1, the sealed gas 5 is cooled to a cryogenic temperature and sublimated as a condensable gas, thereby defining the vacuum heat insulating layer 4. Adhere to the wall. The sealed gas 5 can be any one of carbon dioxide, hydrocarbon gas, inorganic oxide gas, ammonia, and alcohol. The hydrocarbon gas may be chlorofluorocarbon, fluorinate, or acetylene.
[Selection] Figure 1

Description

  The present invention relates to a vacuum heat insulating container having a vacuum heat insulating layer and a method for inserting a sealed gas into the vacuum heat insulating layer.

  Cryostat, cryogenic liquid container, vacuum insulated double tube, vacuum environment device, LNG tank, vacuum device, liquefied oxygen tank, liquefied nitrogen tank, liquefied argon tank, liquefied carbon dioxide tank, etc. Insulation of the device is provided with a vacuum insulation layer having a double wall structure (for example, see Patent Document 1 below). This vacuum heat insulating layer realizes high-performance heat insulation by drawing a gap between the double wall structures into a vacuum.

  Conventionally, a vacuum pump is attached to evacuate the vacuum heat insulating layer of a cryogenic device, and a method of venting the air therein has been used. As for a vacuum heat insulating layer of a large cryogenic device, there are some in which particles such as pearlite are inserted into the vacuum heat insulating layer as a radiation shield for preventing radiation heat transfer.

JP 2000-18494 A

The conventional technique has a problem that it takes a very long time to evacuate the vacuum heat insulating layer provided in the cryogenic apparatus. For example, in the case of a cryogenic liquid storage container, it takes several days to produce it, but it is necessary to perform vacuum evacuation work continuously for one week or more, and there are significant problems in terms of cost and delivery time.
Further, when the cryogenic apparatus becomes large and complicated, the above vacuum evacuation work has a drawback that it takes a long time.

  The time required for the vacuum insulation layer to be evacuated is short, but when high vacuum is reached, the mean free path of air molecules in the vacuum insulation layer becomes extremely long, and the vacuum pump is maintained at a high vacuum. However, since it cannot reach the vacuum pump over obstacles in the pearlite or the vacuum heat insulating layer, a very long venting time is required. For this reason, after manufacturing the cryogenic device, a vacuum evacuation operation of the vacuum heat insulating layer is required, an electric charge for operating the vacuum pump for a long time is applied, and the delivery time of the cryogenic device is extremely long.

The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a vacuum heat insulating container in which an enclosed gas can increase the degree of vacuum of a vacuum heat insulating layer when a cryogenic refrigerant is stored in the container. Yes.
Another object of the present invention is to provide a method for inserting a sealed gas into a vacuum heat insulating layer of a vacuum heat insulating container that can significantly reduce the manufacturing time of a vacuum heat insulating container having a vacuum heat insulating layer.

In order to achieve the above object, the present invention is a vacuum heat insulating container having a vacuum heat insulating layer, wherein a sealed gas is sealed in the vacuum heat insulating layer, the sealed gas is a gas at room temperature, and the sealed gas is an electrode. When the low-temperature refrigerant is put in a vacuum heat insulating container, it sublimates as a condensable gas and is attached to the wall surface defining the vacuum heat insulating layer.
In the above configuration, the sealed gas is preferably any one of carbon dioxide, hydrocarbon gas, inorganic oxide gas, ammonia, and alcohol. The hydrocarbon gas can be any of chlorofluorocarbon, fluorinate, or acetylene.

According to the above configuration, the vacuum heat insulation layer of the vacuum heat insulation container is filled with a sealed gas that sublimates into a solid at a cryogenic refrigerant temperature such as liquid nitrogen or liquid oxygen, such as carbon dioxide. When a cryogenic refrigerant is added, it adheres to the wall surface defining the vacuum heat insulating layer, and the vacuum degree of the vacuum heat insulating layer can be increased.
Furthermore, after the inside of the vacuum layer is evacuated to a low vacuum, by injecting the sealing gas and repeatedly exhausting it, the non-condensable gas such as air is efficiently exhausted, and the inside of the vacuum layer is filled with the sealing gas. I can do it.

  In order to achieve the above object, the method of inserting the sealed gas into the vacuum heat insulating layer of the vacuum heat insulating container according to the present invention is the first method in which the vacuum heat insulating layer is kept at a predetermined temperature and then evacuated to a predetermined pressure. A second step of filling the vacuum insulating layer evacuated to a predetermined pressure and holding it for a predetermined time, and a third step of evacuating the sealed gas sealed in the vacuum thermal insulating layer to a predetermined pressure. And repeating the second and third steps a predetermined number of times, evacuating the sealed gas in the vacuum heat insulating layer to a predetermined pressure, and sealing the sealed gas in the vacuum heat insulating layer, And the third step is repeated a predetermined number of times, and when the enclosed gas is made into a gas at room temperature and the cryogenic refrigerant is put in the vacuum insulation container, the enclosed gas is sublimated as a condensable gas, and the vacuum insulation layer It is characterized by adhering to the wall that defines .

In the above configuration, the sealed gas can be any one of carbon dioxide, hydrocarbon gas, inorganic oxide gas, ammonia, and alcohol. The hydrocarbon gas may be any of chlorofluorocarbon, fluorinate, or acetylene.
According to the above configuration, the exhaust efficiency of the vacuum heat insulating layer can be remarkably improved by using, as a replacement gas, an enclosed gas that sublimates into a solid at a temperature of liquid nitrogen or the like, such as carbon dioxide. Finally, the sealed gas can be sealed at a predetermined pressure inside the vacuum heat insulating layer, and the heat insulating characteristics of the vacuum heat insulating container can be improved.

In the above configuration, in the vacuum exhaust of the third step, a cooling trap using a cryogen is provided in a pipe between the vacuum heat insulating layer and the vacuum pump for exhausting the vacuum heat insulating layer, and the vacuum exhaust is supplied to the vacuum pump and the cooling trap. May be used.
According to the above configuration, the evacuation time of the vacuum heat insulating layer can be further shortened by performing the evacuation of the sealed gas in combination with the cooling trap.

  According to the vacuum heat insulating container of the present invention, since the vacuum heat insulating layer is filled with an enclosed gas such as carbon dioxide that sublimates into a solid at a cryogenic refrigerant temperature such as liquid nitrogen or liquid oxygen, the cryogenic refrigerant is contained in the container. When the gas is added, the sealed gas is cooled to a very low temperature and sublimated into a solid and adheres to the wall surface defining the vacuum heat insulating layer, thereby increasing the vacuum degree of the vacuum heat insulating layer.

  According to the method of inserting the sealed gas into the vacuum heat insulation layer of the vacuum heat insulation container of the present invention, the exhaust gas of the vacuum heat insulation layer can be obtained by using the filled gas such as carbon dioxide that sublimates into a solid at a temperature such as liquid nitrogen as a replacement gas. Since efficiency can be remarkably improved, the manufacturing time of the vacuum heat insulation container which has a vacuum heat insulation layer can be shortened remarkably.

It is a figure which shows schematic structure of the vacuum heat insulation container which concerns on the 1st Embodiment of this invention. It is a schematic diagram which shows the structure of the enclosure apparatus which encloses the enclosure gas to the vacuum insulation layer of a vacuum insulation container. It is a schematic diagram which shows the structure of the modification of the enclosure apparatus shown in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment of vacuum insulation container)
As shown in FIG. 1, the vacuum heat insulating container 1 according to this embodiment includes an inner wall 2 that forms a container portion, an outer wall 3 that surrounds the inner wall 2, and a vacuum heat insulation defined by the inner wall 2 and the outer wall 3. It is comprised from the layer 4 and the sealing gas 5 enclosed with the vacuum heat insulation layer 4. As shown in FIG. Furthermore, a pearlite or radiation shield film material may be inserted into the vacuum heat insulating layer 4.

  As the sealing gas 5, any one of carbon dioxide, hydrocarbon gas, inorganic oxide gas, ammonia, and alcohol can be used. As the hydrocarbon gas 5, any of chlorofluorocarbon, fluorinate, and acetylene can be used. The sealed gas 5 is a gas at normal temperature. When the cryogenic refrigerant 7 is put into a container part formed by the inner wall 2 of the vacuum heat insulating container 1, the sealed gas 5 is cooled to a cryogenic temperature and sublimated as a condensable gas to form a wall surface defining the vacuum heat insulating layer 4. Adhere to. Accordingly, the sealed gas 5 sealed in the vacuum heat insulating layer 4 at normal temperature becomes solid and no gas is present in the vacuum heat insulating layer 4, so that the degree of vacuum of the vacuum heat insulating layer 4 is improved. Thereby, the vacuum heat insulation layer 4 can be maintained at a high degree of vacuum.

  The filling pressure of the sealed gas 5 in the vacuum heat insulating layer 4 is about 0.01 to 2/3 atm in absolute pressure. Further, considering the case of degassing by heating the vacuum heat insulating container 1 at the time of sealing, the pressure in the vacuum heat insulating layer 4 is adjusted to be 1 atm or less in absolute pressure.

(First Embodiment According to Encapsulating Gas Encapsulating Method)
Encapsulation of the sealed gas 5 in the vacuum heat insulating layer 4 of the vacuum heat insulating container 1 according to the embodiment shown in FIG. 1 is carried out using the gas sealing device 10 shown in FIG. This can be performed by evacuating 4 and supplying the sealed gas 5 at a predetermined pressure to the vacuum heat insulating layer 4.

  The gas sealing device 10 includes a vacuum exhaust unit 20 that evacuates the vacuum heat insulating layer 4 of the vacuum heat insulating container 1 and a sealed gas supply unit 30 that supplies the sealed gas 5 to the vacuum heat insulating layer 4.

The evacuation unit 20 includes a first T-type connection part 21 connected to the on-off valve 4A for sealed gas communicating with the vacuum heat insulating layer 4, a pipe 22 connected to the T-type connection part 21, and a pipe 22 A second T-type connection component 23 to be connected and a vacuum pump 25 connected to the second T-type connection component 23 via a vacuum pump opening / closing valve 24 are included. In the illustrated case, the vacuum pump 25 is constituted by a roughing vacuum pump 26 and a high vacuum pump 27. The roughing vacuum pump 26 is, for example, an oil rotary pump. As the high vacuum pump 27, a diffusion pump, a turbo molecular pump, or the like can be used.
Here, a pressure gauge 28 is connected to the branch port 23A that is not on the evacuation side of the first T-type connecting component 21, and the evacuation state by the evacuation unit 20 and the pressure of the sealed gas 5 to be described later are monitored. ing.

  The sealed gas supply unit 30 includes a gas cylinder 31 filled with the sealed gas 5, a gas cylinder open / close valve 32 connected to the gas cylinder 31, and a pipe connecting the gas cylinder open / close valve 32 and the second T-type connection component 23. 34.

Next, a method for encapsulating the encapsulated gas 5 in the vacuum heat insulating layer 4 using the encapsulating apparatus 10 will be described. In the following description, the sealed gas 5 is carbon dioxide.
(1) First, so-called purging is performed in the piping of the sealed gas supply unit 30 so that no gas other than the carbon dioxide 5 exists.
(2) The vacuum heat insulating container 1 and the sealing device 10 are heated to a predetermined temperature, for example, about 100 ° C., for degassing. In the following steps, the temperature is always maintained at a predetermined temperature.
(3) Only the gas cylinder open / close valve 32 is closed, the sealed gas open / close valve 4A and the vacuum pump open / close valve 24 are fully opened, and the air in the vacuum heat insulating layer 4 is exhausted by the oil rotary pump 26. When the predetermined degree of vacuum in the vacuum heat insulating layer 4 is required to be high vacuum, after exhausting by the oil rotary pump 26, the inside of the vacuum heat insulating layer 4 is further evacuated by the high vacuum pump 27 until the predetermined vacuum degree is reached. Evacuate. When the inside of the vacuum heat insulating layer 4 is evacuated to about 10 ⁻³ Torr, the vacuum pump on-off valve 24 is closed.
(4) Next, the gas cylinder on-off valve 32 is opened little by little to introduce carbon dioxide 5 into the vacuum heat insulating layer 4. The filling pressure of the carbon dioxide 5 in the vacuum heat insulating layer 4 is monitored by the pressure gauge 28 and filled with the carbon dioxide 5 until the absolute pressure is about 0.1 atm. After the carbon dioxide 5 is filled to a predetermined pressure, the gas cylinder open / close valve 32 is closed.
(5) Leave for about 30 minutes while maintaining the temperature.
(6) Next, the vacuum pump 25 is operated to fully open the vacuum pump on-off valve 24, and the carbon dioxide 5 filled in the vacuum heat insulating layer 4 is exhausted. After evacuating to about 10 ⁻³ Torr, the vacuum pump opening / closing valve 24 is closed.
(7) Subsequently, the gas cylinder on-off valve 32 is opened little by little, and the carbon dioxide 5 is introduced again. The pressure is monitored by the pressure gauge 28, and the carbon dioxide 5 is charged to an absolute pressure of about 0.1 atm. After the carbon dioxide 5 is filled to a predetermined pressure, the gas cylinder open / close valve 32 is closed.
(8) Leave it for about 30 minutes while keeping the temperature.
(9) Repeat (6), (7) and (8) above twice.
(10) Finally, the vacuum pump 25 is operated again to fully open the vacuum pump on-off valve 24, and the operation of exhausting the carbon dioxide 5 is performed for a predetermined time. This predetermined time is, for example, about 2 hours. The pressure of carbon dioxide 5 is about 10 ⁻³ Torr.
(11) When the above operation is completed, the sealing step of the carbon dioxide 5 in the vacuum heat insulating layer 4 is completed by closing the sealed gas on-off valve 4A.

According to the present invention described above, the exhaust efficiency of the vacuum heat insulating container 1 is remarkably improved by repeatedly filling the carbon dioxide 5 into the exhaust gas of the vacuum heat insulating layer 4 and evacuating the air in the vacuum heat insulating layer 4. When the cryogenic refrigerant 7 such as liquid nitrogen, liquid oxygen, and liquid helium is put into the vacuum heat insulating container 1, the carbon dioxide 5 enclosed in the vacuum heat insulating layer 4 at a predetermined predetermined pressure is sublimated as a condensable gas. And adheres to the low temperature inner surface.
Thereby, the sealed gas 5 made of carbon dioxide or the like that keeps the vacuum heat insulating layer 4 of the vacuum heat insulating container 1 at a high degree of vacuum can be efficiently sealed in the vacuum heat insulating layer 4 of the vacuum heat insulating container 1 in a short time.

(Second Embodiment According to Encapsulating Gas Encapsulating Method)
The method for enclosing the sealed gas 5 in the vacuum heat insulating layer 4 of the vacuum heat insulating container 1 according to this embodiment is as follows. After the vacuum heat insulating container 1 is manufactured, the vacuum heat insulating layer 4 is formed using the gas sealing device 15 shown in FIG. A vacuum can be applied, and the sealed gas 5 having a predetermined pressure can be supplied to the vacuum heat insulating layer 4 and inserted.

The gas sealing device 15 includes a vacuum exhaust unit 20 that evacuates the vacuum heat insulating layer 4 of the vacuum heat insulating container 1, and a sealed gas supply unit 30 that inserts and supplies the sealed gas 5 to the vacuum heat insulating layer 4. The vacuum exhaust part 20 is not different from the vacuum exhaust part 20 shown in FIG. 2 except that a cooling trap 42 is provided. The sealed gas supply unit 30 is the same as that shown in FIG.
The cooling trap 42 is used for the cooling trap to the branch port 43A of the third T-type connection component 43 inserted between the pipes 22 between the first T-type connection component 21 and the second T-type connection component 23. Connection is made via an on-off valve 44. As a cryogen for the cooling trap 42, liquid nitrogen or the like can be used. Since the other configuration of the enclosing device 15 is the same as that of the enclosing device 10, the description thereof is omitted.

Next, a method for encapsulating the encapsulated gas 5 in the vacuum heat insulating layer 4 using the encapsulating device 15 will be described. Also in the following description, the sealed gas 5 is carbon dioxide.
The steps (1) to (5) are the same. The cooling trap 42 is used in a process corresponding to the above (6) (this process will be described below as (6A)).
(6A) The vacuum pump 25 is operated, the vacuum pump on-off valve 24 is fully opened, and the carbon dioxide 5 filled in the vacuum heat insulating layer 4 is exhausted. When the pressure of the carbon dioxide 5 drops to about 1 Torr, the cooling trap opening / closing valve 44 is opened to adsorb the carbon dioxide 5 to the cooling trap 42 to increase the exhaust speed. After evacuating to about 10 ⁻³ Torr, the cooling trap on-off valve 44 and the vacuum pump on-off valve 24 are closed.

By repeating the steps (6A), (7), and (8) a predetermined number of times and performing the steps (9) to (11), the carbon dioxide 5 can be sealed in the vacuum heat insulating layer 4 at a predetermined pressure. .
According to the sealing method described above, since the exhaust speed is increased by using the cooling trap 42 in the step (6A), the evacuation time of the vacuum heat insulating layer 4 can be shortened.

  The filling pressure of carbon dioxide 5 is about 0.01 to 2/3 atm in absolute pressure. It adjusts so that the atmospheric pressure of the vacuum heat insulation layer 4 after heating the vacuum heat insulation container 1 may be 1 atmosphere or less in absolute pressure.

An example of an evacuation procedure for a liquid nitrogen storage container having a capacity of about 10 cubic meters in which pearlite is filled in the vacuum layer is shown below.
(1) Perform initial evacuation with a vacuum pump for 15 hours.
(2) Fill with CO ₂ to 0.1 atm and leave it for about 4 hours.
(3) After the air was sufficiently diffused into CO _2, the exhaust of CO ₂ for 15 hours with a vacuum pump.
(4) Perform (2) and (3) three times.
(5) When the storage container is used, the inside of the vacuum container is maintained at a high vacuum by filling with liquid nitrogen and sublimating the sealed gas.

  The present invention is not limited to the above embodiment, and various modifications are possible within the scope of the invention described in the claims, and these are also included in the scope of the present invention.

1: Vacuum heat insulating container 2: Inner wall 3: Outer wall 4: Vacuum heat insulating layer 4A: Sealing gas opening / closing valve 5: Filling gas 7: Cryogenic refrigerant 10, 15: Sealing device 20: Vacuum exhaust part 21: First T type Connection parts 22, 34: Pipe 23: Second T-type connection part 25: Vacuum pump 26: Roughing vacuum pump 27: High vacuum pump 28: Pressure gauge 30: Filled gas supply unit 31: Gas cylinder 32: For gas cylinder On-off valve 42: Cooling trap 43: Third T-shaped connecting part 44: On-off valve for cooling trap

Claims (9)

A vacuum insulation container having a vacuum insulation layer,
Filled gas is sealed in the vacuum insulation layer,
The enclosed gas is a gas at room temperature,
The vacuum heat insulating container, wherein the sealed gas is sublimated as a condensable gas when a cryogenic refrigerant is put in the vacuum heat insulating container and is attached to a wall surface defining the vacuum heat insulating layer.   2. The vacuum heat insulating container according to claim 1, wherein the sealed gas is any one of carbon dioxide, hydrocarbon gas, inorganic oxide gas, ammonia, and alcohol.   The vacuum heat insulating container according to claim 2, wherein the hydrocarbon gas is any one of chlorofluorocarbon, fluorinate, and acetylene.   The vacuum heat insulating container according to any one of claims 1 to 3, wherein pearlite or a radiation shielding film material is inserted into the vacuum heat insulating layer. A method for inserting sealed gas into a vacuum insulation layer of a vacuum insulation container,
A first step of evacuating the vacuum heat insulating layer to a predetermined pressure after maintaining the predetermined temperature;
A second step of filling the evacuated vacuum heat-insulating layer with a sealing gas to a predetermined pressure and holding it for a predetermined time;
A third step of evacuating the sealed gas sealed in the vacuum heat insulating layer to a predetermined pressure;
Repeat the second and third steps a predetermined number of times,
Evacuating the sealed gas in the vacuum heat insulating layer to a predetermined pressure, and sealing the sealed gas into the vacuum heat insulating layer;
Including
Repeat the second and third steps a predetermined number of times,
When the sealed gas is a gas at room temperature and a cryogenic refrigerant is placed in the vacuum heat insulating container, the sealed gas is sublimated as a condensable gas and attached to the wall surface defining the vacuum heat insulating layer. A method for inserting a sealed gas into a vacuum heat insulating layer of a vacuum heat insulating container.   6. The method for inserting sealed gas into a vacuum heat insulating layer of a vacuum heat insulating container according to claim 5, wherein the sealed gas is any one of carbon dioxide, hydrocarbon gas, inorganic oxide gas, ammonia, and alcohol. .   The method for inserting a sealed gas into a vacuum heat insulating layer of a vacuum heat insulating container according to claim 6, wherein the hydrocarbon gas is any one of chlorofluorocarbon, fluorinate, and acetylene. In the vacuum exhaust of the third step, a cooling trap using a cryogen is provided in a pipe between the vacuum heat insulating layer and a vacuum pump that exhausts the vacuum heat insulating layer,
The method for inserting sealed gas into the vacuum heat insulation layer of the vacuum heat insulation container according to any one of claims 5 to 7, wherein the evacuation is performed using the vacuum pump and the cooling trap.   9. The vacuum heat insulating layer of the vacuum heat insulating container according to claim 5, wherein the sealed gas is inserted into a vacuum heat insulating layer of the vacuum heat insulating container into which pearlite or a radiation shield film material is inserted. How to insert gas into the tube.

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